JPH0541410B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a thin plate cutting method and a thin plate cutting apparatus for cutting an object to be cut, such as a semiconductor material, into thin plates.

(Prior art) Conventionally, for example, when cutting a wafer from a silicon ingot or cutting an ultra-thin wafer from a wafer, the object to be cut is fixed to the work table of a slicing device, and the inner circumferential blade of the slicing device is The object to be cut is brought close to the blade core of the diamond blade, and the object is cut at a constant feed pitch. In this case, after making the first cut, check the deviation of the single crystal orientation of the cut surface using an X-ray method, etc., and adjust the X-axis and Y-axis of the object appropriately before starting the subsequent cuts. ing.

However, in the above conventional cutting method, the original end face of the workpiece is lost during cutting, so the original end face of the workpiece and the rotating blade (diamond blade)
It is impossible to match the slicing surface of the cutting surface, and accurate pitch feeding from the end surface is impossible. For this reason, the material loss at the end face of the expensive workpiece increases, and usually the loss is about 1 to 3%. Furthermore, since the original end face is lost, the center position of the object to be cut becomes unknown, making it impossible to completely divide the object into two. Even if the cutting position could be determined using a microscope, the accuracy would be low. In addition, multiple objects to be cut can be cut continuously.
Even if an attempt is made to divide the cutting object, the position of the object to be cut during operation is unknown, resulting in a significant deviation in the cutting position. In this case, if an attempt is made to temporarily stop the operation and determine the cutting position of the object to be cut, the efficiency of the cutting operation will be significantly reduced.

Therefore, conventionally, it has been considered impossible to divide a wafer for power devices in which impurity diffusion has been performed on both sides into two wafers and obtain two wafers each having a diffusion layer on one side. One side of the diffused wafer was removed by grinding to obtain a power device wafer. However, this conventional method results in large losses of wafer material and increases manufacturing costs.

(Problems to be Solved by the Invention) As described above, conventionally, it has been virtually impossible to align the end surface of the object to be cut with the slicing surface of the rotary blade of the slicing device.

The present invention has been made in view of the above points, and an object thereof is to provide a thin plate cutting method and a thin plate cutting method that can match the end face of the object to be cut with the slicing surface of the blade that cuts the object. The goal is to provide equipment.

[Structure of the invention]

(Means for Solving the Problems) The thin plate cutting method of the present invention specifies the position of the slice surface of the cutting means by cutting a dummy object and detecting the position of the cut surface, and then detects the position of the cut surface. It is characterized in that the end face of the object to be cut is made to coincide with the sliced surface.

Further, the thin plate cutting device includes a cutting means for cutting the object to be cut, a work table whose position is adjustable provided on one side of the slicing surface of the cutting means, and a work table provided on the other side of the slicing surface of the cutting means. Adjust the position so that it is parallel to the desired surface of the placed object placed on the work table, measure the distance to the said object, and find the position of the desired surface of the object. It is characterized by comprising a detection means for detecting, a storage means for storing the distance to the object detected by the detection means, and an adjustment means for adjusting the position of the work table based on the stored distance. There is.

(Function) According to the thin plate cutting method described above, first, a dummy object to be cut is cut by the cutting means and the position of the cut surface is detected. Since this cutting surface coincides with the slicing surface of the cutting means, by detecting the position of this cutting surface, the position of the slicing surface of the cutting means can be specified. Here, the slicing surface refers to the surface on which the cutting means cuts the object to be cut. For example, if the cutting means is a rotary blade, the slicing surface is the rotating surface of the rotary blade. Thereafter, by aligning the end surface of the object to be cut with the specified slice surface, the end surface of the object to be cut and the slice surface of the cutting means can be aligned. For this reason, it becomes possible to accurately cut the object to be cut from its end face.

Further, according to the thin plate cutting device, the position of the placed object placed on the work table is adjusted so that it is parallel to the desired surface, and the distance to the said figurine is measured, and the desired surface of the said figurine is measured. It has a detection means for detecting the position of the surface. Therefore, the position of the desired surface of the placed object can be detected. Furthermore, since the apparatus has a storage means for storing the distance to the object detected by the detection means, the position of a desired surface of the detected object can be stored. Moreover, since the apparatus has an adjusting means for adjusting the position of the work table based on the stored distance, it is possible to reproduce the position of the detected desired surface of the object to be placed.

With such a thin plate cutting device, the position of the detected desired surface of the object to be placed can be reproduced, so that the thin plate cutting method described above can be realized.

Further, this thin plate cutting device has a cutting means, a work table, a detecting means, and an adjusting means as main components, and has a relatively simple structure and can be realized at low cost.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

In FIG. 1, reference numeral 1 denotes an inner peripheral blade (rotary blade) of a slicing device, such as a diamond blade. 2 and 3 are the above diamond blades 1
The object to be cut and the non-contact sensor are arranged to face each other with the slice plane of the object as the center.
Reference numeral 4 denotes an adhesive base on which the object 2 to be cut is placed and adhesively fixed, and this is clamped on the work table of the slicing device.
The non-contact type sensor 3 is, for example, a laser beam type sensor with a distance meter, which detects the distance to the end surface (or cut surface) of the object to be cut 2, and has a distance measurement accuracy of ±3〓m. It is. This sensor 3 is mounted on a manuplate (adjustment table) that can be finely adjusted vertically and horizontally. This manu plate has Y axis (vertical direction), X axis (horizontal direction)
It is possible to scan a maximum of 50 mm, and the angle can be corrected in 30 second increments on both the X and Y axes, and the Z axis (back and forth direction) can be moved in microns.

On the other hand, the object to be cut 2 is the original object to be cut A.
and a dummy cut object B placed a little apart from one end thereof, each of which is adhered onto the adhesive base 4 with a two-component adhesive resin 5. Here, as the original object to be cut A, 50 silicon wafers W, each with both sides fully diffused, were fixed in an ingot shape, and the first dummy wafers B were glued to both ends of each. A second dummy wafer is shown as a dummy cut object B. The specifications of the above silicon wafer W are: diameter 125±0.5mm, N type, resistivity 50~60〓cm, surface orientation (111)±1°, thickness 1200±
10〓m, the finish is JIS1000# lap, double-sided diffusion is phosphorus diffusion, and the diffusion depth is 150±5〓m.
The first dummy wafer b has a diameter of 125±0.5
mm, thickness 600±10〓m, finish JIS1000# lap, second dummy wafer b has a diameter of 125±0.5
mm, thickness is 3 mm or more. And the above wafer W
. . ., each orientation flat is combined and fixed in the form of an ingot with wax (paraffin), and the wax layer thickness is 3 m on average. Furthermore, first dummy wafers b are fixed to both end surfaces of the ingot-shaped wafers W with the wax.

The slicing device is TS-27 (product model name) manufactured by Meyer & Burger, and its diamond blade 1 has a base metal (stainless steel) thickness of 150 mm.
〓m, blade thickness 340〓cm, cutting width 370〓m. In addition, the work table of the above slicing device has Y axis (vertical direction), X axis (horizontal direction)
has been modified to allow angle correction with precision of 30 seconds, and the Z-axis (feed axis) uses the functionality provided by the manufacturer as is.

Next, the method for cutting the wafer is shown in Fig. 2a.
This will be explained with reference to d to d. First, under normal slicing conditions (blade rotation speed 200 rpm, feed speed 50 mm/min), the second dummy wafer B is cut into two pieces at appropriate positions as shown in Figure 2a. Divide into B1 and B2. At this time, the cut plane generated between B1 and B2 is the plane through which the blade passed, and therefore the cut plane is the rotating plane of blade 1,
In other words, it can be thought of as a slice surface.
Next, of the two dummy wafers B1 and B2, B1 on the side closer to the sensor 3 is removed from the adhesive base 4 by the operator's hands. Next, while irradiating and reflecting laser light from the cut surface sensor 3 of the remaining dummy wafer B2, the position of the sensor 3 is scanned in the X direction and the Y direction by the manuplate, so that the cut surface and the sensor position are parallel to each other. Set the sensor position as follows. Furthermore, the sensor 3 detects the distance between the center of the cut surface of the dummy wafer B2 and the sensor 3 after setting the sensor position (or the average distance between the cut surface sensor 3 and the sensor 3). The detection result (the position of the cut plane is memorized. The slice plane of the blade 1 is now specified. Next, the remaining dummy wafer B2 is removed from the adhesive base 4 by the operator's hands. .
Next, as shown in FIG. 2b, one end surface of the ingot (the end surface of the first dummy wafer b) is placed on the sensor 3.
The scanning result is fed back to the work table side, and the end surface is detected by the sensor 3.
control to be parallel to the X and Y scanning planes. Further, the distance to one end surface of the ingot is detected by the sensor 3, and the work table is controlled so that this distance matches a previously stored distance. As a result, the position of the first detected cut surface coincides with the position of one end surface of the ingot.

After making adjustments in this way, adjust the feed pitch of the slicing device to 1203 mm, which corresponds to the wafer thickness.
m, and start slicing as shown in FIG. 2c. As a result, the first silicon wafer W adjacent to the first dummy wafer b located on one end surface of the ingot is accurately divided into two parts and cut, and the second silicon wafer W is cut into two parts as shown in FIG. The subsequent silicon wafers W... are also sequentially divided into two parts. After slicing, each wafer W is peeled off from the adhesive base 4 and cleaned with a solvent.

According to the thin plate cutting method of the above embodiment, the position of the cut surface of the dummy wafer B is first detected, and when cutting the original wafer W, the end surface is aligned with the previously detected cut surface position. Since cutting is started after adjusting the position, there is no material loss of the original wafer W, and the dummy wafer B is
The loss will be small. Moreover, by determining the feeding pitch of the ingot based on the position of the first detected cutting surface, the original cutting position of the wafer W can be accurately set, and a large number of double-sided diffusion wafers W...
It has become possible to easily and accurately divide the In this example, the parallelism of the divided wafers was less than 25〓m and the thickness variation was ±20〓m.

In addition, the equipment used in the above thin plate cutting method has a slicing device, a position-adjustable work table, a non-contact sensor with a distance meter, and a sensor position adjustment table as the main components, and its configuration is comparable. It is simple and can be realized at low cost.

Note that the above sensor does not need to be equipped with a distance meter; it is possible to automatically control the work table by providing a control device that stores the detected distance, compares the stored distance with the new detected distance, and feeds back the comparison results to the work table. It may also be done in a specific manner. Also,
The sensor may be placed near the diamond blade until it detects the position of the end face of the object to be cut, and may be moved to a position where it does not interfere with cutting before starting cutting of the object.

Further, in the above embodiment, an ingot to which a wafer W is bonded is cut, but this is not limited to cutting a wafer from a silicon ingot, cutting other semiconductor materials, and cutting other objects to be cut into thin plates. The present invention can be applied to such cases.

〔Effect of the invention〕

As described above, according to the present invention, there is provided a thin plate cutting method in which the end face of the object to be cut can be easily and accurately matched with the cut surface by the slicing device, and the cutting position of the object to be cut can be set accurately. Furthermore, it is possible to provide a thin plate cutting device that is relatively simple and inexpensive. Therefore, the present invention is extremely effective when, for example, a wafer is continuously divided into two parts.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the thin plate cutting apparatus of the present invention, and FIGS. 2A to 2D are process diagrams showing an embodiment of a thin plate cutting method using the apparatus shown in FIG. 1... Diamond blade, 2... Object to be cut, W... Wafer, B, b... Dummy wafer, 3... Laser light sensor with distance meter, 4...
Adhesive base, 5...Adhesive.

Claims (1)

[Scope of Claims] 1. A step of preparing an object to be cut and a dummy object to be cut, a step of cutting the dummy object to be cut by a cutting means, and a step of determining the position of a cut surface of the dummy object to be cut. The present invention is characterized by comprising the steps of: specifying the position of the slice plane of the cutting means by detection; and adjusting the position of the end face of the object to be cut so that it coincides with the specified slice plane. Thin plate cutting method. 2. A cutting means for cutting an object to be cut; a work table whose position is adjustable provided on one side of the slicing surface of the cutting means; and a work table provided on the other side of the slicing surface of the cutting means, on the work table. a detection means for detecting the position of the desired surface of the figurine by adjusting the position of the figurine so that it is parallel to the desired surface of the figurine, and measuring the distance to the figurine; A thin plate cutting device comprising: a storage means for storing the distance to the object detected by the detection means; and an adjustment means for adjusting the position of the work table based on the stored distance.